Compressor

ABSTRACT

A diaphragm is provided between a frame and a stator of an electric motor. The diaphragm allows a communication passage to communicate with a gap and allows a gas passage to communicate with a discharge space. Refrigerant gas discharged from a compression mechanism flows thoroughly into the gap, passes through a communication space and the gas passage, and then, is discharged from a discharge pipe.

TECHNICAL FIELD

The present invention relates to a compressor, and particularly relatesto a measure for cooling an electric motor.

BACKGROUND ART

Conventionally, as disclosed in Japanese Patent Application Laid OpenPublication No. 5-164069A, Japanese Patent Application Laid OpenPublication No. 10-22381A, and Japanese Patent Application Laid OpenPublication No. 2-169887A, an electric compressor in which a compressionmechanism and an electric motor for driving the compression mechanismare accommodated in a hermetic casing has been known as one type ofcompressors. A compressor of this kind is connected to a refrigerationcircuit of a refrigerating apparatus for compressing refrigerant gas,for example. In this compressor, the compression mechanism includes afixed scroll and a movable scroll, the fixed scroll being fixed to thecasing through a housing. The electric motor is composed of a statorfixed to the casing, a rotor rotatably arranged inside the stator, and adrive shaft fixed to the rotor. The rotor rotates to rotate the driveshaft, thereby driving the compression mechanism. On the other hand, thestator of the electric motor is cut at a part of the outer peripheralportion thereof to form a gap between the casing and the stator.Refrigerant gas compressed by the compression mechanism is allowed toflow into the gap, thereby cooling the electric motor.

—Problems that the Invention is to Solve—

The conventional compressors do not control the flow of the refrigerantgas positively in the casing. For this reason, the refrigerant gas flowsas it takes its natural course in the casing, and then, is dischargedthrough a discharge pipe. The refrigerant has a nature of flowingtowards a part having less resistance, and therefore, the refrigerantgas does not necessarily flow to the gap evenly and may flow ununiformlyin some cases. Thus, the conventional compressors are capable of coolingthe electric motor by the refrigerant gas to some degree but incapableof exhibiting efficient cooling performance to the electric motor.

For example, in a compressor in which the discharge pipe is mounted tothe casing so as to communicate with a space between the compressionmechanism and the electric motor, part of the refrigerant gas dischargedfrom the compression mechanism is discharged through the discharge pipewithout passing through the gap around the stator, resulting inineffective cooling of the electric motor by the refrigerant gas.

The present invention has been made in view of the above problems andhas its object of cooling an electric motor efficiently.

SUMMARY OF THE INVENTION

To attain the above object, in the present invention, gas dischargedfrom a compression mechanism (22) is made to flow from either one of agap (39 a, 3 b) of an electric motor (24) and a gas passage (40) to theother.

Specifically, the first invention provides compressor in which a casing(11) accommodates a compression mechanism (22) and an electric motor(24) that has a stator (33) and drives the compression mechanism (22)and a discharge pipe (18) is connected to the casing (11) at a partbetween the compression mechanism (22) and the electric motor (24), thecompressor including: a gas passage (40) formed from one end to theother end of the electric motor (24) between the stator (33) of theelectric motor (24) and the casing (11), wherein the gas passage (40)leads at one end thereof to a gap (39 a, 39 b) extending inside theelectric motor (24) from one end to the other end of the electric motor(24), and gas discharged from the compression mechanism (22) flows fromeither one of the gap (39 a, 39 b) extending inside the electric motor(24) from one end to the other end of the electric motor (24) and thegas passage (40) to the other, and then, flows into the discharge pipe(18).

The second invention provides a compressor on the premise that a casing(11) accommodates a compression mechanism (22) and an electric motor(24) that has a stator (33) and drives the compression mechanism (22)and a discharge pipe (18) is connected to the casing (11) at a partbetween the compression mechanism (22) and the electric motor (24), thecompressor being characterized by including: a partition member (21)that defines the inside of the casing (11) as a first accommodationspace (13) for the compression mechanism (22) and a second accommodationspace (14) for the electric motor (24); a communication passage (26)that is formed in the partition member (21) for leading gas dischargedfrom the compression mechanism (22) to the second accommodation space(14); a gas passage (40) which is formed between the stator (33) of theelectric motor (24) and the casing (11) so as to extend from one end tothe other end of the electric motor (24) and of which one end leads to agap (39 a, 39 b) extending inside the electric motor (24) from one endto the other end of the electric motor (24); and a diaphragm (42) thatallows the communication passage (26) to communicate with one end of thegap (39 a, 39 b) and allows a discharge space (16) communicating withthe discharge pipe (18) to communicate with the other end of the gaspassage (40).

In the third invention, the diaphragm (42) is formed between thepartition member (21) and the stator (33) of the electric motor (24) inthe second invention.

In the fourth invention, the diaphragm (42) is formed integrally withthe partition member (21) in the third invention.

In the fifth invention, the diaphragm (42) is formed integrally with aniron core (35) of the stator (33) of the electric motor (33) so as tohave a cylindrical shape protruding in an axial direction further than acoil (36) in third invention.

In the sixth invention, the diaphragm (42) is formed by stacking annularsteel plates (42 a) in the third invention.

In the seventh invention, the diaphragm (42) is composed of acylindrical member fitted between the partition member (21) and thestator (33) of the electric motor (24) in the third invention.

In the eighth invention, the communication passage (26) has a flowoutlet open towards a coil (36) of the stator (33) in the secondinvention.

In the ninth invention, an outer peripheral face of the stator (33)adheres to the casing (11) and the gas passage (40) is formed of avertical trench (35 d) formed in an outer peripheral portion of thestator (33) in any one of the first to eighth inventions.

In the tenth invention, the vertical trench (35 d) includes a pluralityof vertical trenches (35 d) formed along a peripheral direction and thedischarge pipe (18) is displaced in the peripheral direction from thevertical trenches (35 d) in the ninth invention.

In the eleventh invention, the number of the vertical trench (35 d) isone and the discharge pipe (18) is provided opposite the vertical trench(35 d) with a drive shaft (23) of the electric motor (24) interposed inthe ninth invention.

In the twelfth invention, the stator (33) of the electric motor (24) ismounted indirectly to the casing (11) through the partition member (21)and the gas passage (40) is formed of a gap formed around the entiretyin a peripheral direction of the stator (33) in any one of the second toeighth inventions.

In the thirteenth invention, the discharge space (16) is formed largerthan a flow outlet of the gas passage (40) in any one of the second totwelfth inventions.

In the fourteenth invention, a coil (36) is wound to each of tooth parts(35 b) of the iron core (35) of the stator (33) in the stator (33) ofthe electric motor (24) in any one of the first to thirteenthinventions.

—Operation—

In the first invention, the gas discharged from the compressionmechanism (22) flows into either one of the gap (39 a, 39 b) of theelectric motor (24) and the gas passage (40) to cool the electric motor(24). Then, the gas flowing out from the one of the gap (39 a, 39 b) ofthe electric motor (24) and the gas passage (40) flows into the otherone of the gap (39 a, 39 b) of the electric motor (24) and the gaspassage (40) to cool the electric motor (24). Then, the gas isdischarged outside the casing (11) through the discharge pipe (18). Inother words, the direction that the gas flows is restrained so that thegas flows from either one of the gap (39 a, 39 b) and the gas passage(40) to the other. Thus, the gas flows smoothly in the casing (11) tocool the electric motor (24).

In the second invention, the gas discharged from the compressionmechanism (22) flows into the second accommodation space (14) throughthe communication passage (26). The gas then flows out from thecommunication passage (26) into the gap (39 a, 39 b) of the electricmotor (24). The gas cools the electric motor (24) when flowing throughthe gap (39 a, 39 b). The gas flowing out from the gap (39 a, 39 b) thenflows into the gas passage (40). This gas cools the electric motor (24)when flowing through the gas passage (40). The gas flowing out from thegas passage (40) passes through the discharge space (16), and then, isdischarged outside the casing (11) through the discharge pipe (18).

In the eighth invention, the gas flowing out from the communicationpassage (26) flows towards the coil (36) of the stator (33). If the gascontains oil, the oil is trapped in the coil (36) to be liquefied.

In the ninth invention, the stator (33) of the electric motor (24) isfixed to the casing (11). The gas flows through the gas passage (40)that the vertical trench (35 d) in the outer peripheral portion of thestator (33) and the casing (11) form.

In the tenth invention, the gas flow through the plurality of gascommunication pipes (40) of the stator (33) which are provided along theperipheral direction. The gas flowing through the gas passages (40)changes its flowing direction in the peripheral direction, and then, isdischarged outside the casing (11) through the discharge pipe (18).

In the eleventh invention, after the gas flows through the gas passage(40) of the stator (33) which is formed at one part, the flowingdirection is changed in the peripheral direction. Then, the gas isdischarged outside the casing (11) through the discharge pipe (18)located opposite the electric motor (24) with the drive shaft (23)interposed.

In the twelfth invention, the stator (33) is mounted indirectly to thecasing (11) through the partition member (21) and a gap is formed aroundthe entirety in the peripheral direction of the outer periphery of thestator (33). The gap forms the gas passage (40) and the gas dischargedfrom the compression mechanism (22) flows through the gas passage (40).

In the thirteenth invention, the discharge space (16) is formed largerthan the flow outlet of the gas passage (40), so that the flow rate ofthe gas flowing out from the gas passage (40) of the stator (33)decreases when the gas flowing out from the gas passage (40) flows intothe discharge space (16). Then, the gas of which flow rate decreases isdischarged outside the casing (11) through the discharge pipe (18).

In the fourteenth invention, a coil (36) is wound to each of the toothparts (35 b) of the iron core (35) of the stator (33). Accordingly, thegaps (39 b) are formed between adjacent teeth (35 b). Hence, the gasflows into the gaps (39 b) between the teeth (35 b) and into the gap (39a) between the stator (33) and the rotor (34).

—Effects—

As described above, according to the first invention, the gas dischargedfrom the compression mechanism (22) can flow into both the gap (39 a, 39b) and the gas passage (40). Further, the direction that the gas flowsis restrained, achieving smooth and thoroughgoing flow of the gas insideand outside of the electric motor (24). As a result, the electric motor(24) is cooled by the gas efficiently.

According to the second invention, the gas discharged from thecompression chamber (22) can flow into the gap (39 a, 39 b) inside theelectric motor (24) thoroughly and securely. Further, the gas flowingout from the gap (39 a, 39 b) can flow into the gas passage (40) surely,and then, be discharged outside the casing (11). As a result, the gasdischarged from the compression mechanism (22) cools the electric motor(24) efficiently. Further, the path from the compression mechanism (22)to the discharge pipe (18) can be set long, so that a larger amount ofoil in a case using gas containing oil can be separated.

In the third invention, the diaphragm (42) is provided between thepartition member (21) and the stator (33) of the electric motor (24), sothat the gas flowing into the second accommodation space (14) towardsthe electric motor (24) can be restrained surely.

In the fourth invention, the diaphragm (42) is formed integrally with apart of the partition member (21) on the electric motor side (24), sothat the space between the partition member (21) and the stator (33) canbe partitioned surely with no additional process for the stator (33) ofthe electric motor (24) necessitated.

In the fifth invention, the diaphragm (42) is formed integrally with theiron core (35) of the stator (33) so as to protrude in the axialdirection further than the coil (36). Accordingly, the diaphragm (42)can be clamped between the partition member (21) and the iron core (35)of the stator (33), thereby surely partitioning the space between thepartition member (21) and the stator (33).

In the sixth invention, the annular steel plates (42 a) are stacked toform the diaphragm (42). Accordingly, the space between the partitionmember (21) and the stator (33) of the electric motor (24) can bepartitioned surely in such a simple manner that only the steel plate (42a) are stacked, with no additional process for the partition member (21)necessitated.

In the seventh invention, the diaphragm (42) is formed of a memberfitted between the partition member (21) and the stator (33) of theelectric member (24), so that the space between the partition member(21) and the stator (33) can be partitioned surely with no additionalprocess for the partition member (21) and the stator (33) necessitated.

In the eighth invention, the gas flowing out from the communicationpassage (26) is made to flow towards the coil (36) of the stator (33),so that oil contained in the gas is trapped by the coil (36) to beliquefied. Thus, the oil can be separated from the gas efficiently andis prevented from being discharged together with the gas dischargedthrough the discharge pipe (18).

In the ninth invention, the stator (33) of the electric motor (24) isfixed to the casing (11) and the vertical trench (35 d) to serve as thegas passage (40) is formed in the stator (33). Accordingly, the gas canflow outside the stator (33) while the supporting rigidity of theelectric motor (24) is enhanced.

In the tenth invention, the plurality of gas passages (40) are formedalong the peripheral direction and the discharge pipe (18) is displacedin the peripheral direction with respect to the vertical trenches (35d), so that cooling can be performed in a plurality of directionsoutside the stator (33), achieving efficient cooling of the electricmotor (24). Further, the path from the compression mechanism (22) to thedischarge pipe (18) can be set long, so that a larger amount of oil in acase using gas containing oil can be separated.

In the eleventh invention, the discharge pipe (18) is mounted on theside opposite the gas passage (40), so that the gas flowing path up to apart where the gas is discharged from the discharge pipe (18) can be setto the maximum, attaining separation of a larger amount of oil in a caseusing gas containing oil.

In the twelfth invention, the stator (33) is mounted indirectly to thecasing (11) through the partition member (21). Accordingly, the gasflows around the entirety of the outer periphery of the stator (33),attaining further efficient cooling of the electric motor (24) whilesecurely supporting the electric motor (24).

In the thirteenth invention, the flow rate of the gas decreases beforethe gas flows into the discharge pipe (18), so that a larger amount ofoil in a case using gas containing oil can be separated.

In the fourteenth invention, the coil (36) of the stator (33) arewounded to each of the tooth parts (35 b) of the iron core (35), so thatthe gaps (39 a, 39 b) inside the electric motor (24) can be set wider.As a result, the gas can flow into the gaps (39 a, 39 b) efficiently andsurely, improving the cooling efficiency of the electric motor (24).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section showing a whole construction of a compressoraccording to Embodiment 1 of the present invention.

FIG. 2 is a section showing a construction of a stator of an electricmotor in Embodiment 1 of the present invention.

FIG. 3 is a section taken along the line III-III in FIG. 1.

FIG. 4 is a section showing a whole construction of a compressoraccording to Embodiment 2 of the present invention.

FIG. 5 is a section showing a whole construction of a compressoraccording to Embodiment 3 of the present invention.

FIG. 6 is a section showing a whole construction of a compressoraccording to Embodiment 4 of the present invention.

FIG. 7 is a section taken along the line VII-VII in FIG. 6.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below in detailwith reference to the drawings. Wherein, the present invention is notlimited to the following embodiments.

Embodiment 1

Embodiment 1 of the present invention is applied to a scroll compressorfor compressing refrigerant gas which is connected to a refrigerationcircuit (not shown) of a refrigeration apparatus that performs a vaporcompression refrigeration cycle, for example.

As shown in FIG. 1, a compressor (10) according to the presentembodiment includes a casing (11) composed of a pressure vessel. Thecasing (11) accommodates a frame (21) as a partition member fixed to thecasing (11), a scroll type compression mechanism (22) mounted at theupper end of the frame (21), and an electric motor (24) having a driveshaft (23) and arranged under the frame (21). The frame (21) is arrangedbetween the compression mechanism (22) and the electric motor (24). Theinside of the casing (11) is defined as a first accommodation space (13)located upper than the frame (21) and accommodating the compressionmechanism (22) and a second accommodation space (14) located lower thanthe frame (21) and accommodating the electric motor (24). The secondaccommodation space (14) is formed of a communication space (15) locatedunder the electric motor (24) and a discharge space (16) ranging betweenthe frame (21) and the electric motor (24).

To the casing (11), an intake pipe (17) and a discharge pipe (18) aremounted. The intake pipe (17) passes through the casing (11) and isfitted in the compression mechanism (22). The discharge pipe (18) passesthrough the casing (11) and opens at the inner end thereof to thedischarge space (16).

The frame (21) adheres and is fixed at the outer peripheral face thereofto the inner peripheral face of the casing (11) by, for example,pressing to fit the frame (21) to the upward part of the casing (11). Inthe upper part of the frame (21), an upper face concave portion (21 a)is formed so as to be bowed downward at the central part thereof.Further, the outer peripheral concave portion (21 b) is formed aroundthe entirety of the outer periphery of the frame (21) so as to be bowedinward. A disk-shaped flange (21 c) extending horizontally towards thecasing (11) is formed at the lower end of the outer peripheral concaveportion (21 b) of the frame (21).

The frame (21) is provided with a bearing portion (21 d) under the upperface concave portion (21 a). This bearing portion (21 d) is composed ofa sleeve bearing to support one end (upper end) of the drive shaft (23)of the electric motor (24) rotatably.

Further, a communication passage (26) is formed so as to pass throughthe frame (21) vertically. The communication passage (26) has a flowinlet formed so as to open to the first accommodation space (13) in apart of the upper end face of the frame (21) which is located furtheroutward than a fixed scroll (27) and a flow outlet formed so as to opento the second accommodation space (14) in a part of the lower end faceof the flange (21 c).

The discharge pipe (18) passes through the casing (11) at a part betweenthe electric motor (24) and the part where the frame (21) adheres to thecasing (11). Further, the discharge pipe (18) communicates with thedischarge space (16) between the casing (11) and the outer peripheralconcave portion (21 b) of the frame (21).

The compression mechanism (22) includes the fixed scroll (27) and amovable scroll (28). The fixed scroll (27) is mounted at the peripheralpart thereof on the upper face of the frame (21) so as to be fixed tothe frame (21). Each scroll (27, 28) is composed of a head (27 a, 28 a)and a spiral lap (27 a, 28 b) formed at the head (27 a, 28 a). The laps(27 a, 28 b) of the scrolls (27, 28) mesh with each other.

The movable scroll (28) is arranged between the fixed scroll (27) andthe frame (21). A rotation inhibiting member (30) such as an Oldhamcoupling is provided between the head (28 a) of the movable scroll (28)and the frame (21) so that the movable scroll (28) performs onlyrevolution around the fixed scroll (27).

The space where the laps (27 b, 28 b) contact with each other betweenthe head (27 a) of the fixed scroll (27) and the head (28 a) of themovable scroll (28) serves as a compression chamber (32). A dischargehole (27 d) for discharging high-pressure refrigerant passes through thecentral part of the head (27 a) of the fixed scroll (27).

The intake pipe (17) is fitted in the head (27 a) of the fixed scroll(27). The inner end of the intake pipe (17) opens to a refrigerant gasintake chamber (27 c) formed at the peripheral part of the lap (27 b).

A cylindrically protruding boss (28 c) is formed at the central part ofthe lower face of the head (28 a) of the movable scroll (28). The upperend part of the drive shaft (23) is fitted to the boss (28 c). The upperend part of the drive shaft (23) is eccentric from the axial center ofthe drive shaft (23). The bearing portion (21 d) of the frame (21)supports the drive shaft (23) at a part just under the upper end part ofthe drive shaft (23). In other words, the electric motor (24) isconnected to the frame (21) through the drive shaft (23).

A seal ring (31) is arranged around the boss (28 c) and is fitted to theupper face concave portion (21 a) of the frame (21) so as to be incontact with and press the lower face of the head (28 a) of the movablescroll (28). This seal ring (31) serves to prevent the high-pressure gasrefrigerant flowing inside the upper face concave portion (21 a) fromleaking peripherally further than the seal ring (31) and serves to allowthe movable scroll (28) to be in contact with and press the fixed scroll(27) by the high-pressure force of the high-pressure gas refrigerant.

The electric motor (24) is arranged immediately below the bearingportion (21 d) of the frame (21). The electric motor (24) is composed ofa blushless DC motor, for example, and includes a stator (33) and arotor (34) arranged inside the stator (33). The drive shaft (23) isconnected to the rotor (34) so as to rotate integrally with the rotor(34).

The stator (33) is composed of a stator iron core (35) and coils (36)fitted to the stator iron core (35), as shown in FIG. 2 and FIG. 3. Thestator iron core (35) includes an annular iron core body (35 a) fixed toand pressed in the casing (11) and teeth (35 b) as tooth parts formed soas to protrude inward of the iron core body (35 a).

The stator iron core (35) is composed such that multiple electromagneticsteel plates (35 c) punched out by sheet metal stamping are stacked, asshown in FIG. 2. Each of the electromagnetic steel plates (35 c)includes an annular portion serving as the annular iron core body (35 a)and substantially rectangular portions serving as the teeth (35 b).

The teeth (35 b) of plural in number (6 in the present embodiment) areformed along the peripheral direction. Each tip end of the teeth (35 b)forms an arc so that a cylindrical space is formed further inside thanthe tip ends of the teeth (35 b).

The rotor (34) is composed such that a permanent magnet (34 b) isembedded in a cylindrical rotor iron core (34 a) formed by stackingelectromagnetic plates punched out by metal stamping. The rotor (34) isarranged so that a gap (39 a) having a predetermined width between therotor (34) and the teeth (35 b) is formed in the space formed fartherinside than the teeth (35 b).

The stator (33) employs concentrated winding (series winding) forwinding the coils (36). Namely, the coils (36) are wound individually tothe teeth (35 b) of the stator iron core (35). A gap (39 b) having apredetermined width is formed between each pair of adjacent teeth (35b).

The gaps (39 a, 39 b) are formed from the upper end to the lower end ofthe electric motor (24). The lower ends of the gaps (39 a, 39 b) open tothe communication space (15) under the electric motor (24).

Vertical trenches (35 d) are formed by cutting out parts of the outerperipheral portion along the peripheral direction of the iron core body(35 a) of the stator iron core (5).

The vertical trenches (35 d) are formed correspondingly to the teeth (35b) so as to be long and narrow in the peripheral direction and so as toextend across the entirety in the axial direction. The vertical trenches(35 d) and the casing (11) form gas passages (40) that allow therefrigerant gas to flow therethrough. Namely, the gas passages (40) areformed from one end to the other end of the electric motor (24). Eachlower end of the gas passages (40) opens to the communication space(15), so that the gas passages (40) leads at the lower end thereof tothe gaps (39 a, 39 b).

The discharge pipe (18) is displaced in the peripheral direction fromthe vertical trenches (35 d). In other words, the discharge pipe (18) islocated immediately above a part between one pair of adjacent verticaltrenches (35 d).

In the second accommodation space (14), a diaphragm (42) is formed asshown in FIG. 1 and FIG. 2. The diaphragm (42) is in a cylindrical shapeand arranged so as to connect the flange (21 c) of the frame (21) andthe iron core body (35 a) of the stator iron core (35). Whereby, thespace between the frame (21) and the stator (33) is defined as insideand outside spaces. The diaphragm (42) is composed such that apredetermined number of the annular electromagnetic steel plates (42 a)not having parts forming the teeth (35 b), namely, composing only theiron core body (35 a) are stacked. The diaphragm (42) is made longerthan the length of a part of the coils (36) which protrudes in the axialdirection from the end in the axial direction of the stator iron core(35). The predetermined number of electromagnetic steel plates (42 a)are stacked on the stacked body of the electromagnetic steel plates (35c) composing the stator iron core (35), so that the upper end of thediaphragm (42) is in contact with the lower end of the flange (21 c) ofthe frame (12).

To the space inside the diaphragm (42), the flow outlet of thecommunication passage (26) of the frame (21) opens and the upper ends ofthe gaps (39 a, 39 b) open as flow inlets. On the other hand, to thespace outside the diaphragm (42), the upper ends of the gas passages(40) open as flow outlets and communicate with the discharge space (16).

Namely, the diaphragm (42) sets the communication passage (26) tocommunicate with the upper ends of the gaps (39 a, 39 b) while settingthe discharge space (16) and the gas passages (40) to communicate witheach other.

In the communication space (15), a bearing plate (44) and an oilreservoir (45) are provided. The bearing plate (44) is fixed to thecasing (11) and supports the lower end of the drive shaft (23)rotatably. Oil reserved in the oil reservoir (45) is supplied to each ofsliding parts such as the compression mechanism (22), the bearingportion (21 d), and the like through an oil supply passage (not shown)formed inside the drive shaft (23).

—Operation—

The operation of the compressor (10) according to the present embodimentwill be described next. First, when the electric motor (24) startsoperating, the rotor (34) rotates relative to the stator (33) to rotatethe drive shaft (23). In association with the rotation of the driveshaft (23), the movable scroll (28) revolves around the fixed scroll(27) without rotation. This makes a low-pressure refrigerant to besucked into the compression chamber (32) from the intake pipe (17) tochange the volume of the compression chamber (32), thereby compressingthe refrigerant. This refrigerant becomes high in pressure by thecompression, and then, is discharged to the first accommodation space(13) from the discharge hole (27 d). The refrigerant gas contains oil.Namely, part of the oil supplied from the oil reservoir (45) to thecompression mechanism (22) is discharged to the first accommodationspace (13) together with the refrigerant gas.

The refrigerant gas filled up in the first accommodation space (13) islead to the second accommodation space (14) through the communicationpassage (26). At that time, the refrigerant flowing out from thecommunication passage (26) flows thoroughly into the space inside thediaphragm (42) towards the coils (36) of the electric motor (24) in thepresence of the diaphragm (42). Accordingly, part of the oil containedin the refrigerant gas is trapped by the coils (36) to be liquefied.This means that the liquefied oil is separated from the refrigerant gas.Thereafter, the refrigerant gas flows into the gaps (39 a, 39 b) of theelectric motor (24).

Part of the refrigerant gas flows downward through the gap (39 a)between the stator (33) and the rotor (34) while the other part of therefrigerant gas flows downward through the gaps (39 b) between the teeth(35 b). At this time, the refrigerant gas cools the electric motor (24)while flowing through the gaps (39 a, 39 b). The refrigerant gas flowsout into the communication space (15) from the lower ends of the gaps(39 a, 39 b). The communication space (15) has a passage area largerthan the total passage area of the gaps (39 a, 39 b), so that the flowrate of the refrigerant gas decreases in the communication space (15).Accordingly, part of the oil contained in the refrigerant gas isseparated also in the communication space (15).

Thereafter, the refrigerant gas flows upward into the gas passages (40).At this time, the refrigerant gas cools the electric motor (24) whileflowing through the gas passages (40). Namely, the refrigerant gas flowsdownward through the gaps (39 a, 39 b) and flows upward through the gaspassages (40). This means restraint of the direction that therefrigerant gas flows in the casing (11).

The refrigerant gas flowing out from the gas passages (40) passesthrough the outside of the diaphragm (42) and flows into the dischargespace (16). The discharge space (16) is enlarged wider than the flowoutlets of the gas passages (40) to decrease the flow rate of therefrigerant gas in the discharge space (16). Accordingly, part of theoil contained in the refrigerant gas is separated also in the dischargespace (16). Subsequently, the refrigerant gas changes in its flowingdirection in the discharge space (16), and then, is discharged outsidethe casing (11) through the discharge pipe (18).

Effects in Embodiment 1

As described above, according to the compressor (10) in Embodiment 1,the refrigerant gas discharged from the compression mechanism (22) ismade to thoroughly flow into either the gaps (39 a, 39 b) of theelectric motor (24) and the gas passages (40). Further, the diaphragm(42) restricts the direction that the refrigerant gas flows to make therefrigerant gas flowing out from the communication passage (26) to flowthoroughly into the gaps (39 a, 39 b) surely. As a result, therefrigerant gas cools the electric motor (24) efficiently.

Further, in Embodiment 1, the refrigerant gas flows from the gaps (39 a,39 b) to the gas passages (40) and the refrigerant gas flowing out fromthe gas passages (40) is discharged through the discharge pipe (18).Accordingly, the discharge pipe (18) is only required to communicate atthe inner end thereof with the discharge space (16), simplifying theconstruction thereof.

Furthermore, in Embodiment 1, the diaphragm (42) is composed of thepredetermined number of electromagnetic steel plates (42 a) stacked onthe stator iron core (35). This simple scheme of stacking theelectromagnetic steel plates (42 a) enables sure partitioning betweenthe frame (21) and the stator (33) with no additional process for theframe (21) necessitated. Also, the diaphragm (42) protrudes in the axialdirection further than the coils (36), being clamped between the frame(2.1) and the stator iron core (35). This enables sure partitioning ofthe space between the frame (21) and the stator (33).

Moreover, in Embodiment 1, the flow outlet of the communication passage(26) opens towards the coils (36) of the stator (33), so that therefrigerant gas flowing out from the communication passage (26) flowstowards the coils (36). Accordingly, the coils (36) traps oil containedin the refrigerant gas to liquefy it, resulting in efficient separationof oil from the refrigerant gas. This suppresses discharge of oil fromthe discharge pipe (18) together with the gas.

Further, in Embodiment 1, the stator (33) of the electric motor (24) isinserted by pressing in the casing (11) and the vertical trenches (35 d)are formed by cutting out parts of the outer peripheral portions of thestator (33), thereby forming the gas passages (40) of the gaps betweenthe vertical trenches (35 d) and the casing (11). Hence, the refrigerantgas can flow outside the stator (33) surely while the supportingrigidity of the electric motor (24) increases.

Furthermore, in Embodiment 1, the discharge pipe (18) is displaced inthe peripheral direction from the vertical trenches (35 d), so that therefrigerant gas changes its flowing direction in the peripheraldirection after flowing upward through the gas passages (40) formedalong the peripheral direction. This means cooling in the pluraldirections from the outside of the stator (33), resulting in efficientcooling of the electric motor (24). Further, a larger amount of oilcontained in the refrigerant gas can be separated because therefrigerant path up to the part where it is discharged from thedischarge pipe (18) can be set longer.

Moreover, in Embodiment 1, the discharge space (16) is enlarged widerthan the flow outlets of the gas passages (40) of the stator (33), sothat the flow rate of the refrigerant gas decreases when the refrigerantgas flowing from the gas passages (40) flows into the discharge space(16). Then, the refrigerant gas of which flow rate decreases isdischarged outside the casing (11) through the discharge pipe (18).Thus, the decrease in flow rate of the refrigerant gas before flowinginto the discharge pipe (18) attains separation of a larger amount ofoil contained in the refrigerant gas before it flows into the dischargepipe (18).

In addition, in Embodiment 1, the concentrated winding is employed forthe coils (36) so that the coils (36) are wound individually to theteeth (35 b) of the stator iron core (35), and accordingly, the gaps (36b) are formed between adjacent teeth (35 b). This increases the area ofthe passages through which the refrigerant gas flows, resulting inefficient and sure flow of the refrigerant gas into the gaps (39 a, 39b) and in increase in cooling efficiency of the electric motor (24).

Embodiment 2

FIG. 4 shows Embodiment 2 of the present invention. Wherein, the samereference numerals are assigned to the same constitutional elements asthose in Embodiment 1 and the detailed description thereof is omitted.

In Embodiment 2, the diaphragm (42) is formed of a part of the frame(21). Specifically, the flange (21 c) of the frame (21) is in the diskshape, as described above, and extends at the outer peripheral endthereof downward to form the diaphragm (42). Namely, the diaphragm (42)is integrally formed with a part of the frame (21) on the electric motor(24) side. The diaphragm (42) is in a cylindrical shape concentric withthe drive shaft (23) and has a length in the axial direction longer thanthe length of a part of the coils (36) of the electric motor (24) whichprotrudes from the end face in the axial direction of the stator ironcore (35). Further, the lower end of the diaphragm (42) is in contactwith the upper end of the iron core body (35 a) of the stator iron core(35).

Hence, according to Embodiment 2, the space between the frame (21) andthe stator (33) can be partitioned surely with no additional process forthe stator (33) of the electric motor (24) necessitated. The otherconstitution, operations, and effects of the present embodiment are thesame as those in Embodiment 1.

Embodiment 3

FIG. 5 shows Embodiment 3 of the present invention. Wherein, the samereference numerals are assigned to the same constitutional elements asthose in Embodiment 1 and the detailed description thereof is omitted.

In Embodiment 3, the diaphragm (42) is composed of a cylindrical memberseparately from the frame (21) and the stator (33 b) of the electricmotor (23). This diaphragm (42) is set longer than the length of a partof the coils (36) of the electric motor (23) which protrudes in theaxial direction from the end face in the axial direction of the statoriron core (35). Further, the diaphragm (42) is fitted between the flange(21 c) of the frame (21) and the stator (33) of the electric motor (24)so as to be concentric with the drive shaft (23). The upper end of thediaphragm (42) is in contact with the lower end of the flange (21 c)while the lower end thereof is in contact with the upper end of the ironcore body (35 a) of the stator iron core (35).

Hence, according to Embodiment 3, the space between the frame (21) andthe stator (33) can be partitioned surely with no additional process forthe frame (21) and the stator (33) necessitated. The other constitution,operations, and effects of the present embodiment are the same as thosein Embodiment 1.

Embodiment 4

FIG. 6 shows Embodiment 4 of the present invention. Wherein, the samereference numerals are assigned to the same constitutional elements asthose in Embodiment 1 and the detailed description thereof is omitted.

In Embodiment 4, the stator (33) of the electric motor (24) is fixedindirectly to the casing (11) through the frame (21). Specifically, thestator iron core (35) of the stator (33) has an outer diameter smallerthan the inner diameter of the casing (11), and is arranged a distanceleft from the inner face of the casing (11). A through hole (35 e) isformed in the iron core body (35 a) of the stator iron core (35) forallowing a bolt (51) to pass therethrough. The stator (33) is arrangedsuch that the diaphragm (42) is clamped between the stator (33) and theframe (21), and is fastened and fixed to the flange (21 c) of the frame(21) by means of the bolt (51) inserted in the through hole (33 f)

A gap formed between the casing (11) and the stator (33) so as to have apredetermined width forms a gas passage (40). Namely, as describedabove, the outer diameter of the stator iron core (35) is smaller thanthe inner diameter of the casing (11) to form the gap between the casing(11) and the stator (33) around the entirety in the peripheral directionof the stator (33). This gap forms the gas passage (40) through whichthe refrigerant gas is allowed to flow. Wherein, the vertical trenches(35 d) are not formed in the outer peripheral part of the stator (33) inEmbodiment 4.

Hence, in Embodiment 4, the refrigerant gas flows around the entirety ofthe outer periphery of the stator (33), so that efficient cooling of theelectric motor (24) is attained while the electric motor (24) issupported firmly. The other constitution, operations, and effects of thepresent embodiment are the same as those in Embodiment 1.

Other Embodiments of the Invention

In Embodiments 1 to 3, a plural number of gas passages (40) are formedalong the peripheral direction of the stator (33). Instead, only one gaspassage (40) may be formed. In this case, it is preferable to arrangethe discharge pipe (18) opposite the gas passage (40) with the driveshaft (23) interposed. By doing so, the refrigerant gas flowing path upto the part where the refrigerant gas is discharged from the dischargepipe (18) can be set to the maximum, enabling separation of a largeramount of oil contained in the refrigerant gas.

Further, in each of the above embodiments, the stator iron core (35) ofthe electric motor (24) is composed of stacked layers of theelectromagnetic steel plates (35 c). However, the present invention isnot limited to this composition and the stator iron core (35) may becomposed of an integral member formed of a dust iron core, for example.

Moreover, the diaphragm (42) is composed of stacked layers of thepredetermined number of electromagnetic plates (42 a) on the upper faceof the stator iron core (35) in Embodiment 1, but may be formedcylindrically and integrally with the stator iron core (35). Forexample, the stator iron core (35) and the diaphragm (42) may beintegrally formed of a dust iron core or the like. In this constitution,also, the diaphragm (42) is required to protrude in the axial directionfurther than the coils (36).

In each of the embodiments, the generally-called concentrated winding isemployed for the stator (33) of the electric motor (24). Instead, theremay be employed a generally-called distributed winding in which a coil(36) is wound to a plurality of teeth (35 b).

Referring to Embodiment 4, the diaphragm (42) may be composed of a partof the frame (21) which extends downward from the flange (21 c) or maybe composed of a cylindrical member separately from the frame (18) andthe stator (33).

Furthermore, in each of the embodiments, the refrigerant gas flowing outfrom the communication passage (26) flows through the gaps (39 a, 39 b),and then, flows through the gas passages (40) to be discharged from thedischarge pipe (18). On the contrary, the refrigerant gas flowing outfrom the communication passage (26) may flow through the gas passages(40), and then, flow through the gaps (39 a, 39 b) to be discharged fromthe discharge pipe (18).

In addition, the scroll compressor (10) is employed in each of theembodiments, but the compressor is not limited to the scroll type andmay be of rotary piston type.

INDUSTRIAL APPLICABILITY

As described above, the present invention is useful for compressors ofwhich casing accommodates a compression mechanism and an electric motor.

1. A compressor comprising: a casing having a discharge pipe; acompression mechanism disposed in the casing; and an electric motorhaving a stator that drives the compression mechanism, a first endportion and a second end portion with a gap extending inside theelectric motor between the first end portion and the second end portion,the stator of the electric motor being configured and arranged relativeto the casing to form a gas passage therebetween that extends from thefirst end portion of the electric motor to the second end portion of theelectric motor, the gas passage being configured and arranged in fluidcommunication with the gap such that gas discharged from the compressionmechanism flows from one of the gap and the gas passage to the other,and then, flows into the discharge pipe.
 2. A compressor comprising: acasing having a discharge pipe and a partition member configured andarranged to partition the casing to define a first accommodation spaceinside of the casing and a second accommodation space inside of thecasing; a compression mechanism disposed in the first accommodationspace of the casing, the compression mechanism being arranged such thatgas discharged from the compression mechanism passes through acommunication passage disposed in the partition member to the secondaccommodation space; an electric motor disposed in the secondaccommodation space of the casing, the electric motor having a statordrives the compression mechanism, the stator of the electric motor beingconfigured and arranged relative to the casing to form a gas passagetherebetween that extends from a first end portion of the electric motorto a second end portion of the electric motor, one end of the gaspassage leading to a gap extending inside the electric motor from thefirst end portion of the electric motor to the second end portion of theelectric motor; and a diaphragm configured to allow the communicationpassage to communicate with an end of the gap and allow a dischargespace coupled with the discharge pipe to communicate with the gaspassage.
 3. The compressor of claim 2, wherein the diaphragm is formedbetween the partition member and the stator of the electric motor. 4.The compressor of claim 3, wherein the diaphragm is formed integrallywith the partition member.
 5. The compressor of claim 3, wherein thediaphragm is formed integrally with an iron core of the stator of theelectric motor so as to have a cylindrical shape protruding in an axialdirection further than a coil.
 6. The compressor of claim 3, wherein thediaphragm is formed by stacking annular steel plates.
 7. The compressorof claim 3, wherein the diaphragm includes a cylindrical member disposedbetween the partition member and the stator of the electric motor. 8.The compressor of claim 2, wherein the communication passage has a flowoutlet opened towards a coil of the stator.
 9. The compressor claims 1,wherein an outer peripheral face of the stator adheres to the casing,and the gas passage includes a vertical trench formed in an outerperipheral portion of the stator.
 10. The compressor of claim 9, whereinthe vertical trench includes a plurality of vertical trenches formedalong a peripheral direction, and the discharge pipe is displaced in theperipheral direction from the vertical trenches.
 11. The compressor ofclaim 9, wherein the discharge pipe is provided opposite the verticaltrench with a drive shaft of the electric motor interposed.
 12. Thecompressor of claim 2, wherein the stator of the electric motor ismounted indirectly to the casing through the partition member, and thegas passage is formed around an entirety of an outer peripheral surfaceof the stator.
 13. The compressor of claims 2, wherein the dischargespace is larger than a flow outlet of the gas passage.
 14. Thecompressor of claims 1, wherein the stator of the electric motor, has acoil wound onto each of a plurality of tooth parts of an iron core ofthe stator.
 15. The compressor of claim 2, wherein the stator of theelectric motor has a coil wound onto each of a plurality of tooth partsof an iron core of the stator.
 16. The compressor claim 2, wherein anouter peripheral face of the stator adheres to the casing, and the gaspassage includes a vertical trench formed in an outer peripheral portionof the stator.
 17. The compressor of claim 16, wherein the verticaltrench includes a plurality of vertical trenches formed along aperipheral direction, and the discharge pipe is displaced in theperipheral direction from the vertical trenches.
 18. The compressor ofclaim 16, wherein the discharge pipe is provided opposite the verticaltrench with a drive shaft of the electric motor interposed.